Monday, August 11, 2008

Tropical Starfish Conservation: A partial guide to other fished species

Last week I looked at Protoreaster nodosus, one of the more frequently encountered dried tropical starfish species and I thought I would partly continue that theme and continue looking at other species that I've encountered which are probably fished a LOT of in the dry shell trade.

There are some regional species that one sees on sale, but that don't seem to make it far beyond their home range (although they still make it to online sales).

In nearly all cases below, biology about reproduction is absent or poorly understood. Archaster is a predator of small sand invertebrates and the rest are all essentially microalgal or biofilm feeders similar to Protoreaster.

I'm omitting cold-water species like Pisaster or Asterias, which are also heavily "fished" because there's so much known about these species relative to their tropical counterparts.

Most of the following taxa are species I've seen over and over again in shell shops or for sale online. Some of these species are also seen a lot in the pet trade, which is another issue.

The most frequently encountered species I've encountered include: Protoreaster and Archaster, followed by Linckia with the others occurring less frequently.

Archaster (probably Archaster typicus, Fam. Archasteridae)
Apparently one of the most commonly encountered shallow-water tropical species. Known professionally as the "faux Astropecten" because of its convergent appearance with astropectinid sand stars.
Archaster occurs with some abundance on sandy bottoms throughout the Indo-Pacific.

Archaster gets collected by the THOUSANDS. and in different size classes. Large to small sized individuals get collected and sold. The lot below was 100+ specimens at a size range of about 2-5 cm diameter. This begs any numer of questions about this species' carrying capacity.Linckia spp. (Fam. Ophidiasteridae)

The most commonly encountered tropical Pacific species is Linckia laevigata, but other species of Linckia exist throughout the tropics in the Pacific and the Atlantic which are used in shells and artsy things. Linckia columbiae from the Mexico/Baja area and Linckia guildingi from the tropical Atlantic/Pacific.
Members of this species occur with some abundance in the shell-trade. Mostly those species that aren't asexual. The fissiparous ones are presumably not as visually appealing.
Oreaster reticulatus (Family Oreasteridae)

This species occurs in the tropical Atlantic and has been heavily fished, leading to localized extinction in some parts. Unlike its Indo-Pacific counterparts, quite a bit of this species biology has been studied by Rob Scheibling and Anna Metaxas.
This species is heavily fished, dried and sold. I haven't see this species as frequently on sale as Protoreaster and relative to Protoreaster, the populations are apparently larger (see Scheibling & Metaxas 2008).

That being said, they have been rendered locally extinct in different parts of the tropical Atlantic.
Pentaster obtusatus (Fam. Oreasteridae)

Not as frequently seen in the shell-trade, but where Protoreaster is found for sale, this species is usually present. They co-occur and are often collected together.

Its not known how abundant this species is and whether it has anywhere near the capacity to withstand the fishing pressure.

Pentaceraster spp. (Family Oreasteridae)

There are several species in this genus and biology isn't well known for most species in Pentaceraster. I haven't seen too many of these. They don't seem to be nearly as abundant or as frequently available as Archaster, Protoreaster, or Linckia.

1 comment:

Jives said...

I like the barrels of starfish organized by color. That way you KNOW you're getting a yellow one.